1. Field
The present disclosure relates to mask frame assemblies for deposition of thin films, and more particularly, to mask frame assemblies using split masks, and methods of manufacturing the mask frame assemblies.
2. Description of the Related Art
In general, among display devices, organic light-emitting display devices provide a wide viewing angle, an excellent contrast ratio, and a high response speed.
Organic light-emitting display devices realize colors based on the principle that holes and electrons injected from an anode and a cathode recombine in an emissive layer and emit light. Thus, organic light-emitting display devices have a stacked structure in which the emissive layer is inserted between the anode and the cathode. However, it is difficult to achieve high emission efficiency using this structure, and thus intermediate layers such as an electron injection layer, an electron transport layer, a hole transport layer, and a hole injection layer are selectively inserted between the electrodes and the emissive layer.
The electrodes and the intermediate layers such as the emissive layer of the organic light-emitting display devices may be formed using various methods, and one of these is a deposition method. In order to manufacture an organic light-emitting display device using a deposition method, a fine metal mask (FMM) having the same pattern as a pattern of a thin film that is to be formed on a substrate is aligned on the substrate, and a material used to form the thin films is deposited to form a thin film having a desired pattern.
However, if the FMM becomes too large, etching errors also increase during forming patterns. Thus, split masks are used. The split masks are formed of a various number of stick-shaped masks and attached to a frame. That is, a mask device for use in depositing a plurality of screens of organic light-emitting display devices on a mother substrate is used, whereas since it is difficult to cover the entire surface of the mother substrate using a single mask without any etching errors, several split masks in the form of sticks having a predetermined width are attached to the frame to form the mask device.
Recently, the screens of the organic light-emitting display devices become large, and the size of a unit screen to be deposited become larger than a single split mask. That is, a maximum width of a split mask which would be able to avoid an etching error is about 150 mm and deposition patterns corresponding to screens having 7 inches or smaller size may be formed using this split mask. However, to accommodate a deposition pattern corresponding, for example, to a 14-inch screen, the split mask needs to have a width of about 300 mm. When forming a split mask having a width of 300 mm or greater, etching errors increase.
The foregoing discussion in the background section is to provide general background information, and does not constitute an admission of prior art.